Efficient segmentation of the left atrium (LA) wall from delayed enhancement MRI is challenging due to inconsistent contrast, combined with noise, and high variation in atrial shape and size. We present a surface-detection method that is capable of extracting the atrial wall by computing an optimal a-posteriori estimate. This estimation is done on a set of nested meshes, constructed from an ens...

A branch-and-cut mixed integer programming system, called bc − opt, is described, incorporating most of the valid inequalities that have been used or suggested for such systems, namely lifted 0-1 knapsack inequalities, 0-1 gub knapsack and integer knapsack inequalities, flowcover and continuous knapsack inequalities, path inequalities for fixed charge network flow structure and Gomory mixed int...

Branch and cut methods for integer programming problems solve a sequence of linear programming problems. Traditionally, these linear programming relaxations have been solved using the simplex method. The reduced costs available at the optimal solution to a relaxation may make it possible to fix variables at zero or one. If the solution to a relaxation is fractional, additional constraints can b...

We describe a robust but simple algorithm to reconstruct a surface from a set of merged range scans. Our key contribution is the formulation of the surface reconstruction problem as an energy minimisation problem that explicitly models the scanning process. The adaptivity of the Delaunay triangulation is exploited by restricting the energy to inside/outside labelings of Delaunay tetrahedra. Our...

We address the problem of improving the scene cut quality in fixed bit-rate real-time video decoding such as is used in the H.263 and MPEG standards. In low bandwidth applications, scene cuts can cause the bits required to encode a single frame to greatly exceed the target average bits per frame, and necessitate the skipping of other frames to provide sufficient time to transmit the scene cut f...

In this paper we propose an iterative graph cuts based active contours approach to segment an object boundary out of background. Given an initial boundary nearby the object, the graph cuts based active contour can iteratively deform to the object boundary even if there are large discontinuities and noise. In each iteration, the area of interest is a certain neighborhood of the previously estima...

We investigate a logistics facility location problem to determine whether the existing facilities remain open or not, what the expansion size of the open facilities should be and which potential facilities should be selected. The problem is formulated as a mixed integer linear programming model (MILP) with the objective to minimize the sum of the savings from closing the existing facilities, th...

We study an extended trust region subproblem minimizing a nonconvex function over the hollow ball $$r \le \Vert x\Vert R$$ intersected with full-dimensional second order cone (SOC) constraint of form $$\Vert x - c\Vert b^T a$$ . In particular, we present class valid cuts that improve existing semidefinite programming (SDP) relaxations and are separable in polynomial time. connect our to literat...

The class of mathematical programs with complementarity constraints (MPCCs) constitutes a powerful modeling paradigm. In an effort to find a global optimum, it is often useful to examine the relaxation obtained by omitting the complementarity constraints. We discuss various methods to tighten the relaxation by exploiting complementarity, with the aim of constructing better approximations to the...